Manual measurements of nitrous oxide (N₂O) emissions with static chambers are commonly practised. However, they generally do not consider the diurnal variability of N₂O flux, and little is known about the patterns and drivers of such variability. We systematically reviewed and analysed 286 diurnal data sets of N₂O fluxes from published literature to (i) assess the prevalence and timing (day or night peaking) of diurnal N₂O flux patterns in agricultural and forest soils, (ii) examine the relationship between N₂O flux and soil temperature with different diurnal patterns, (iii) identify whether non‐diurnal factors (i.e. land management and soil properties) influence the occurrence of diurnal patterns and (iv) evaluate the accuracy of estimating cumulative N₂O emissions with single‐daily flux measurements. Our synthesis demonstrates that diurnal N₂O flux variability is a widespread phenomenon in agricultural and forest soils. Of the 286 data sets analysed, ~80% exhibited diurnal N₂O patterns, with ~60% peaking during the day and ~20% at night. Contrary to many published observations, our analysis only found strong positive correlations (R > 0.7) between N₂O flux and soil temperature in one‐third of the data sets. Soil drainage property, soil water‐filled pore space (WFPS) level and land use were also found to potentially influence the occurrence of certain diurnal patterns. Our work demonstrated that single‐daily flux measurements at mid‐morning yielded daily emission estimates with the smallest average bias compared to measurements made at other times of day, however, it could still lead to significant over‐ or underestimation due to inconsistent diurnal N₂O patterns. This inconsistency also reflects the inaccuracy of using soil temperature to predict the time of daily average N₂O flux. Future research should investigate the relationship between N₂O flux and other diurnal parameters, such as photosynthetically active radiation (PAR) and root exudation, along with the consideration of the effects of soil moisture, drainage and land use on the diurnal patterns of N₂O flux. The information could be incorporated in N₂O emission prediction models to improve accuracy.

To store substantial amounts of carbon in natural climate solutions the strong interlinkages between carbon and nitrogen cycling must be considered. There are many agricultural management options for...

Metatranscriptomic analysis of the soil microbiome has the potential to reveal molecular mechanisms that drive soil processes regulated by the microbial community. Therefore, RNA samples must be of sufficient yield and quality to robustly quantify differential gene expression. While short-read sequencing technology is often favoured for metatranscriptomics, long-read sequencing has the potential to provide several benefits over short-read technologies. The ability to resolve complete transcripts on a portable sequencing platform for a relatively low capital expenditure makes Oxford Nanopore Technology an attractive prospect for addressing many of the challenges of soil metatranscriptomics. To fully enable long-read metatranscriptomic analysis of the functional molecular pathways expressed in these diverse habitats, RNA purification methods from soil must be optimised for long-read sequencing. Here we compare RNA samples purified using five commercially available extraction kits designed for use with soil. We found that the Qiagen RNeasy PowerSoil Total RNA Kit performed the best across RNA yield, quality and purity and was robust across different soil types. We found that sufficient sequencing depth can be achieved to characterise the active community for total RNA samples using Oxford Nanopore Technology, and discuss its current limitations for differential gene expression analysis in soil studies.